https://bugzilla.wikimedia.org/show_bug.cgi?id=38136
Web browser: ---
Bug #: 38136
Summary: [SMW] Patch: SMW_refreshData.php delay time * 100
causes high server load
Product: MediaWiki extensions
Version: unspecified
Platform: All
OS/Version: All
Status: NEW
Severity: critical
Priority: Unprioritized
Component: Semantic MediaWiki
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected], [email protected]
Classification: Unclassified
Mobile Platform: ---
Created attachment 10816
--> https://bugzilla.wikimedia.org/attachment.cgi?id=10816
Patch resolving the "bug".
SMW_refreshData.php takes a delay parameter that is supposed to slow the
progress of the refresh for each SMW ID. However, for some reason the delay
time is multiplied by 100 and then applied only for blocks of 100 ID's. That
causes 100% server load while the 100 ID's are being processed, even while
idle. In most cases we tested, it caused otherwise idle servers to be sluggish
to respond to even a single HTTP request.
If other refresh operations are in progress, or the MediaWiki job queue is
running, the problem can compound until the server grinds to a halt, and the
refresh on the block of 100 ID's never completes. Then, the server won't even
respond to SSH connection attempts for a reboot command, and it must be
manually power-cycled. This was tested on a variety of servers. We tested a 2.5
GHz dual-core server with 8 GB RAM before we realized it was a flaw in SMW, not
the server.
I don't know why the code prevents the delay from applying to each SMW ID, and
the comments do not explain. The fix was simple, and I have attached a patch.
This is my first patch, so go easy on me if something isn't correct. It appears
my text editor removed some superfluous white space too, but that shouldn't
matter.
I tested my changes on SMW 1.7.0.2, but supplied a patch for the version of
SMW_refreshData.php that is included in SMW 1.7.1. We haven't upgraded to test
1.7.1 yet, but these changes are so trivial, I doubt they would make any
difference. It appears SMW_refreshData.php has no changes in SMW 1.7.1 that
would produce different results from what we tested.
--
Configure bugmail: https://bugzilla.wikimedia.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.
You are on the CC list for the bug.
_______________________________________________
Wikibugs-l mailing list
[email protected]
https://lists.wikimedia.org/mailman/listinfo/wikibugs-l
